In recent years, with the spread of therapy using molecular target drugs based mainly on antibody drugs, quantitating biological substances (antigens) in cells of the observation target has been desired for more efficient design of the molecular target drugs. For confirming the presence of a biological substance, a method of organization analysis is known on the basis of the binding of a fluorescent substance bonded with biological substance recognition site and a biological substance which bind the biological substance recognition site.
Patent Document 1 suggests a method for identifying specific cells and quantification, including staining a tissue slice with a fluorescent dye and calculating the area and the luminance level of light emitting parts (see line 13 in lower right column on page 3 to line 8 in upper left column on page 4; lines 10 to 14 in lower left column on page 4, etc.).
Unfortunately, according the method, the number and the location of biological substances in cells cannot be obtained accurately on the basis of luminance level, because emitted lights superimpose with each other when there are many biological substances in a specific small area in one cell.
In contrast, Patent Document 2 describes a method for calculating the number of bright points per cell, including staining a tissue slice with a fluorescent particle and measuring fluorescent bright points using a confocal microscope (see Examples 1-2).